Even when you've switched to a 64bit-version of windows and ccm+, you might experience a bad performance. When meshing takes about 3.5GB of memory, the solver will need a similar amount of memory. And swapping memory to the hard disk is not very efficient.

Thank you. So typically how much memory is required for 3D airfoil simulation? What could be the possible solution in this circumstances? Should I be in 32bit version instead of switching?

Quote:

Originally Posted by abdul099

Even when you've switched to a 64bit-version of windows and ccm+, you might experience a bad performance. When meshing takes about 3.5GB of memory, the solver will need a similar amount of memory. And swapping memory to the hard disk is not very efficient.

I know that there is a difference but with that hardware no good job is possible.
Work with coarse grid - maybe. But efficient work is not possible.

4GB RAM and 32bit OS. Fastest solution (time from now till solution) is to work with 2 CPUs to be able to use that 4GB RAM.
When that isn't enough - sure he needs 64bit. But he also need 64bit OS etc. And maybe also more memory.
Installing all needs longer that make that 2 CPU 32bit try-run. More than a try-run it can't be with that hardware.

Well, I did some wing simulations some time ago. The wing was a piece of the wing, with a length about 4.5m (7.5m semi-span for the whole wing). My mesh had about 35 million cells which took about 20GB memory. Of course, it wasn't ideal, from the current point of view, some tuning would have been necessary.
If you are seriously interested in simulating wings, you can't get over switching to 64bit and invest some money in buying suitable hardware.
With your current hardware, you might be able to simulate a slice of the airfoil, but nothing which has to do with 3-dimensional effects of the flow field.

Quote:

Originally Posted by shamim

Abdul

Thank you. So typically how much memory is required for 3D airfoil simulation? What could be the possible solution in this circumstances? Should I be in 32bit version instead of switching?

And Maddin, you're right When running a case in parallel, every thread will only need a part of the memory. But first, shamim still doesn't get a mesh and meshing is a serial process - at least for now. And second, a 32bit operating system can handle a maximum of 4GB per process. Just assuming the solver will need the same amount of memory than the mesher (just a rule of thumb), shamim will not benefit even from running it in parallel due to the maximum amount of memory already being used by one process.

JBeilke, STAR-CCM+ doesn't need a headnode suitable to handle the whole model. Otherwise you would never be able to run a Formula 1 car on a cluster. The master process needs slightly more memory than the other computing processes, but not that much more.
You just need a big machine for meshing, or a lot of time and a tough hard disk (for swapping) - of course all with a 64bit OS.

And Maddin, you're right When running a case in parallel, every thread will only need a part of the memory. But first, shamim still doesn't get a mesh and meshing is a serial process - at least for now. And second, a 32bit operating system can handle a maximum of 4GB per process.

He can mesh that grid without problem.
He have to split the regions and he must select mesh by region.
It only needs more time.

With windows you only can access to 2GB memory per thread.
To use 4GB RAM you have to use 2 threads (run with 2 CPUs).

Quote:

JBeilke, STAR-CCM+ doesn't need a headnode suitable to handle the whole model. Otherwise you would never be able to run a Formula 1 car on a cluster. The master process needs slightly more memory than the other computing processes, but not that much more.
You just need a big machine for meshing, or a lot of time and a tough hard disk (for swapping) - of course all with a 64bit OS.

I think nowadays the memory is no problem. 16GB costs ~200 Euro (DDR3-PC1600), for desktop hardware you don't need ECC.
I'd like to use QUDA for my desktop work

That's not right. Sure, a 32bit Windows will use only 3.2GB instead of 4, but even 4Gb is only like a drop in the bucket, compared with the usual ressources most people are using for airfoil simulation.
Therefore the problem is not the operating system. The problem are the available ressources.